A diving whale off the coast of Southern California near the Los Angeles suburb of Palos Verdes in 2010. Mike Nelson/EPA/Landov hide caption

itoggle caption Mike Nelson/EPA/Landov

The sea ice that polar bears use as a platform to catch seals is shrinking, threatening the species' existence. U.S. Fish and Wildlife Serivce/AP hide caption

itoggle caption U.S. Fish and Wildlife Serivce/AP

Mountain lion 38F perches in a tree before getting a tracking collar from the Santa Cruz Puma Project. Peter Lollo/KQED hide caption

itoggle caption Peter Lollo/KQED

A Humane Society investigation of a Wyoming pig breeding facility to the introduction of an ag-gag bill in Wyoming, which eventually failed. Courtesy of Humane Society of the U.S. hide caption

itoggle caption Courtesy of Humane Society of the U.S.

A newly discovered neural circuit in the brain of the common fruit fly seems to serve as a sort of "volume control," turning up and down the perception of sound and light. Nicholas Monu/iStockphoto hide caption

itoggle caption Nicholas Monu/iStockphoto

A technique called optogenetics is being used in the laboratory to observe and control what brain circuits are doing in real time. Henning Dalhoff/Getty Images/Science Photo Library RM hide caption

itoggle caption Henning Dalhoff/Getty Images/Science Photo Library RM

(Clockwise, from left)Yuanzai; Mei Huan; Happy Leopard; Mei Lun; Xing Bao; Bao Bao. (Clockwise, from left) Xinhua/Landov; Courtesy of Zoo Atlanta; Animal Press/Barcroft Media/Landov; Courtesy of Zoo Atlanta; EPA/Sergio Barrenechea/Landov; Abby Wood/UPI/Landov hide caption

itoggle caption (Clockwise, from left) Xinhua/Landov; Courtesy of Zoo Atlanta; Animal Press/Barcroft Media/Landov; Courtesy of Zoo Atlanta; EPA/Sergio Barrenechea/Landov; Abby Wood/UPI/Landov

The Texas Camel Corps guides camel treks through the Big Bend region of Texas, where such animals once served American settlers in the late 1800s. Wade Goodwyn/NPR hide caption

itoggle caption Wade Goodwyn/NPR